Electronic device furnished with a conducting layer and method of fabrication

ABSTRACT

An electronic device includes a support board having a mounting face and an integrated circuit chip mounted on the mounting face. An encapsulation block embeds the integrated circuit chip, the encapsulation block extending above the integrated circuit chip and around the integrated circuit chip on the mounting face of the support board. The encapsulation block includes a front face with a hole passing through the encapsulation block to uncovering at least part of an electrical contact. A layer made of an electrically conducting material fills the hole to make electrical connection to the electrical contact and further extends over the front face of the encapsulation block.

PRIORITY CLAIM

This application claims priority from French Application for Patent No.1557998 filed Aug. 28, 2015, the disclosure of which is incorporated byreference.

TECHNICAL FIELD

The present invention relates to the field of electronic devices.

BACKGROUND

Known electronic devices, generally of parallelepipedal shape, comprisea support board, including an electrical connection network, anintegrated circuit chip mounted on one of the faces of the support boardand an encapsulation block in which the chip is embedded. The chip islinked to the network of the support board by electrical connectionelements, such as balls, interposed between the support board and thechip, or by electrical connection wires embedded in the encapsulationblock.

Such electronic devices are mounted on printed circuit boards, generallyby way of electrical connection elements, such as balls, linking theelectrical connection network of the support boards and the electricalconnection network of the printed circuit boards.

When the chips generate radiofrequency signals having to be transmittedor when they process radiofrequency signals received, the transmit orreceive antennas are produced on the printed circuit boards. Theelectrical signals follow very long resistive paths which consist oflines of the electrical connection network of the printed circuitboards, the electrical connection elements between the printed circuitboards and the support boards, lines of the electrical connectionnetwork of the support boards and the electrical connection elementsbetween the support boards. Such paths depend furthermore on the qualityof the interconnections arising from fabrication.

The arrangements hereinabove constitute a handicap notably when thenecessary dimension of the antennas, for the transmission ofradiofrequency signals at frequencies of the order of a gigahertz orgreater, or indeed much greater, than a gigahertz, becomes reduced.

SUMMARY

According to one embodiment, there is proposed an electronic devicewhich comprises a support board exhibiting a mounting face, at least oneintegrated circuit chip mounted on the mounting face of the supportboard, an encapsulation block in which the chip is embedded, thisencapsulation block extending above the chip and around the chip on themounting face of the support board and exhibiting a front face, at leastone through hole passing through the encapsulation block and uncoveringat least in part an electrical contact of the mounting face of thesupport board or of the chip, and at least one layer made of anelectrically conducting material, extended over the front face of theencapsulation block and linked to the electrical contact in the hole.

The electrical contact can be fashioned on the mounting face of thesupport board, remote from the periphery of the chip.

The electrical contact can be fashioned on a front face of the chip.

The encapsulation block can exhibit at least one groove in the frontface, in which the conducting layer extends.

There is also proposed a method for fabricating an electronic device, inwhich use is made of a primary electronic device which comprises asupport board, an integrated circuit chip mounted on a mounting face ofthe support board and an encapsulation block extending above the chipand around the chip on the mounting face of the support board, theencapsulation block exhibiting a front face parallel to the supportboard.

The method comprises: producing a hole through the encapsulation blockof the primary electronic device, from the front face, until at leastpartially uncovering an electrical contact; depositing an electricallyconducting liquid or pasty material on at least one zone of the frontface of the encapsulation block and in the hole; and hardening theconducting material, so as to produce a conducting layer linked to theelectrical contact.

The method can comprise: producing at least one groove in the front faceof the encapsulation block, this groove emerging in the hole; theconducting material being subsequently deposited in this groove.

The method can comprise: producing at least two holes through theencapsulation block of the primary electronic device, from the frontface, until at least partially uncovering two electrical contacts;depositing the electrically conducting liquid or pasty material on atleast one zone of the front face of the encapsulation block and in theholes; and hardening the conducting material, so as to produce aconducting layer linked to the electrical contacts.

BRIEF DESCRIPTION OF THE DRAWINGS

Electronic devices and their modes of fabrication will now be describedby way of exemplary embodiments, illustrated by the drawing in which:

FIG. 1 represents a section through an electronic device;

FIG. 2 represents a view from above of the electronic device of FIG. 1;

FIG. 3 represents a step of fabrication, in section, of the electronicdevice of FIG. 1;

FIG. 4 represents another step of fabrication, in section, of theelectronic device of FIG. 1;

FIG. 5 represents another step of fabrication, in section, of theelectronic device of FIG. 1;

FIG. 6 represents another step of fabrication, in section, of theelectronic device of FIG. 1;

FIG. 7 represents a section through another electronic device; and

FIG. 8 represents a section through another electronic device.

DETAILED DESCRIPTION

As illustrated in FIGS. 1 and 2, according to an exemplary embodiment afinal electronic device 1 comprises a support board 2, including anelectrical connection network 3, an integrated circuit chip 4 mounted ona front mounting face 5 of the support board 2 and an encapsulationblock 6 in which the chip 4 is embedded and which extends over the chip4, around the latter, on the mounting face 5 of the support board 2, insuch a way that the electronic device 1 takes the form of aparallelepiped.

According to one variant embodiment represented, the integrated circuitchip 4 is mounted on a mounting face 5 of the support board 2 by way ofelectrical connection elements 7, such as balls, which selectively linkthe chip 4 and the electrical connection network 3. According to anothervariant embodiment, the chip 4 could be glued on the mounting face 5 ofthe support board 2 and be linked to the electrical connection network 3by electrical connection wires embedded in the encapsulation block 6.

According to one variant embodiment represented, the encapsulation block6 exhibits a through hole 8 fashioned from a front face 9 of this block,parallel to the support board 2, until uncovering an electrical contact10 of the electrical connection network fashioned on the mounting face 5of the contact board. The through hole 8 is situated remote from theperiphery of the chip 4 and from the periphery of the primaryencapsulation block 6 and between same.

In the front face 9 of the encapsulation block 6 is fashioned anelongate groove 11 which emerges in the hole 8. For example, the groove11 can pass above and remote from the chip 4.

The encapsulation block 6 is furnished with a layer 12 made of anelectrically conducting material, extended over a zone of its front face9 and which approximately fills the through hole 8 so as to be connectedto the electrical contact 10 in this hole.

More precisely, the conducting layer 12 extends in the groove 11 so asto approximately fill this groove 11. The layer 12 is held by anadhesion effect on the encapsulation block 6.

The conducting layer 12 can be made of a hardened resin includingelectrically conducting metallic particles.

Moreover, the electronic device 1 can be furnished with elements forexterior electrical connection 3 a, such as balls, disposed onelectrical contacts 3 b of the electrical connection network 3 fashionedon a face 2 a of the support board 2, opposite the mounting face 5,these electrical contacts 3 b being linked selectively to the electricalconnection network 3 of the support board 2.

The final electronic device 1 can be produced in the following manner.

As illustrated in FIG. 3, use is made of a prefabricated primaryelectronic device 13 which comprises the support board 2, the chip 4mounted as described above and the encapsulation block 6, the latterexhibiting a completely flat front face 9.

As illustrated in FIG. 4, the hole 8 and the elongate groove 11 areproduced.

Next, according to a variant embodiment illustrated in FIG. 5, aconducting layer 12 made of a liquid or pasty material, that is to sayone able to creep or flow, is deposited in the hole 8 and in the groove11 by means of a mobile syringe 14, the quantity of material depositedbeing able to approximately fill the hole 8 and the groove 11, thelatter constituting a barrier to the creep of the material.

Or else, according to another variant embodiment illustrated in FIG. 6,a quantity of conducting material 15 largely filling the hole 8 and thegroove 11 is deposited and a scraping of this deposited material 15 isundertaken by means of a spatula 16 by moving the latter over the frontface 9 of the encapsulation block 6 so as to leave only the conductinglayer 12.

Next, a hardening of the deposited layer 12 is undertaken, for exampleunder the effect of a radiation.

As illustrated in FIG. 7, according to another exemplary embodiment afinal electronic device 17 is differentiated from the electronic device1 described previously by the fact that, this time, the conducting layer12 is linked directly to a specific electrical contact 18 provided onthe front face 19 of the chip 4. The specific electrical contact 18 canresult from the formation of an electrical link passing through thesubstrate of the integrated circuit chip 4, known by the name TSV(“Through Silicon Via”).

In this exemplary embodiment, the fabrication step equivalent to thatdescribed with reference to FIG. 4 consists in producing a hole 20 in alocation situated above the chip 4, through an encapsulation block 6, soas to uncover the electrical contact 18, and in producing a groove 21emerging in this hole 20. The following steps in producing a conductinglayer 12 are equivalent to those described with reference to FIGS. 5 and6.

The electronic devices which have just been described can arise from acollective fabrication on a common support plate. The encapsulationblocks and the extra encapsulation blocks can be obtained by spreadingof a liquid material, for example an epoxy resin, and then by hardeningof this material.

The electronic devices which have just been described can arise fromcollective fabrication on a common support plate, as is known in thefield of microelectronics.

Of course, the conducting layer 12 can exhibit any desired topographicalshape.

The conducting layer 12 of the electronic devices which have just beendescribed can advantageously constitute an electromagnetic antenna forthe transmission/reception of radiofrequency signals at very highfrequencies (reaching a gigahertz or greater than a gigahertz, or indeedseveral hundred gigahertz), linked to the chip 4 by short electricalconnection paths, via the electrical connection network of the supportboard 2 (FIGS. 1-2) or directly (FIG. 7).

Nonetheless, according to a variant embodiment illustrated in FIG. 8, aconducting layer 12, for example produced in the form of a strip, canconstitute an extra passive electronic component, such as a resistanceor a choke, whose ends can be linked to the chip 4, via the electricalconnection network 3 and/or directly, thereby constituting a bridge.

Accordingly, the ends of this conducting layer 12 can be linked, via twoholes 22 and 23 fashioned through the encapsulation block 6 from itsfront face, in a manner equivalent to that described previously, toelectrical contacts 24 and 25 fashioned either on the front face of thesupport board 2, or on the front face of the chip 4, or one on the frontface of the support board and the other on the front face of the chip.

1. An electronic device, comprising: a support board having a mountingface; an integrated circuit chip mounted on the mounting face of thesupport board; an encapsulation block embedding the integrated circuitchip, said encapsulation block extending above the integrated circuitchip and around the integrated circuit chip on the mounting face of thesupport board, said encapsulation block further having a front face; ahole passing through the encapsulation block and uncovering at least inpart an electrical contact of one of the mounting face of the supportboard or the integrated circuit chip; and a layer made of anelectrically conducting material that extends over the front face of theencapsulation block and is connected to the electrical contact in thehole.
 2. The device according to claim 1, wherein the electrical contactis located on the mounting face of the support board remote from aperiphery of the integrated circuit chip.
 3. The device according toclaim 1, wherein the electrical contact is located on a front face ofthe integrated circuit chip.
 4. The device according to claim 1, whereinthe encapsulation block includes a groove in the front face, and whereinthe layer of electrically conducting material is located within thegroove to form a conducting layer. 5-7. (canceled)
 8. An electronicdevice, comprising: an encapsulation block embedding an integratedcircuit chip, said encapsulation block including a first opening that atleast partially uncovers a first electrical contact; and a layer made ofan electrically conducting material that extends over a front face ofthe encapsulation block and is connected to the first electrical contactin the first opening.
 9. The device of claim 8, wherein the layercompletely fills the first opening.
 10. The device of claim 8, whereinsaid first electrical contact is a contact on the integrated circuitchip.
 11. The device of claim 8, wherein said first electrical contactis a contact on a support substrate, said integrated circuit chipmounted to said support substrate.
 12. The device of claim 8, whereinsaid encapsulation block further includes a second opening that at leastpartially uncovers a second electrical contact; and wherein said layermade of the electrically conducting material that extends over the frontface of the encapsulation block to electrically connect the firstelectrical contact to the second electrical contact.
 13. An electronicdevice, comprising: a primary electronic device comprising a supportboard and an integrated circuit chip mounted on a mounting face of thesupport board; an encapsulation block encapsulating the primaryelectronic device and having a front face parallel to the support board,wherein said encapsulation block includes a first hole extending throughthe encapsulation block from said front face to at least partiallyuncover a first electrical contact; and an electrically conductingmaterial in said first hole in electrical connection with the firstelectrical contact and extending on at least one zone of the front faceof the encapsulation block.
 14. The device according to claim 13,further comprising: a groove in the front face of the encapsulationblock, said groove connecting to said first hole; wherein theelectrically conducting material fills said groove.
 15. The deviceaccording to claim 13, wherein said encapsulating block hole furthercomprises a second hole extending through the encapsulation block fromsaid front face to at least partially uncover a second electricalcontact; wherein said electrically conducting material is further insaid second hole in electrical connection with the second electricalcontact.
 16. The device according to claim 15, wherein said electricallyconducting material extending on said at least one zone of the frontface of the encapsulation block electrically interconnects the first andsecond electrical contacts.
 17. The device according to claim 16,wherein said electrically conducting material extending on said at leastone zone of the front face of the encapsulation block forms an antenna.18. The device according to claim 16, wherein said electricallyconducting material extending on said at least one zone of the frontface of the encapsulation block forms a choke.
 19. The device accordingto claim 16, wherein said electrically conducting material extending onsaid at least one zone of the front face of the encapsulation blockforms a coil.